WASHINGTON — A panel of three federal judges held Monday that North Carolina’s congressional districts were unconstitutionally gerrymandered to favor Republicans over Democrats and said it may require new districts before the November elections, possibly affecting control of the House.
The judges acknowledged that primary elections have already produced candidates for the 2018 elections but said they were reluctant to let voting take place in congressional districts that courts twice have found violate constitutional standards.
North Carolina legislators are likely to ask the Supreme Court to step in. The court traditionally does not approve of judicial actions that can affect an election so close to the day voters go to the polls.
But the Supreme Court has just eight members since Justice Anthony Kennedy’s retirement last month, and a tie vote would leave the lower court’s decision in place. Senate hearings on President Trump’s nominee to fill the open seat, Judge Brett Kavanaugh, commence Tuesday.
The North Carolina case is a long-running saga, with a federal court in 2016 striking down the legislature’s 2011 map as a racial gerrymander. The legislature then passed a plan that left essentially the same districts in place but said lawmakers were motivated by politics, not race.
The Supreme Court told the three-judge panel to take another look at the North Carolina case in light of the high court’s June decision in a Wisconsin gerrymandering case, in which the justices said those who brought that case did not have legal standing.
But Judge James Wynn of the US Court of Appeals for the 4th Circuit said plaintiffs did have standing under the decision in Wisconsin’s Gill v. Whitford, which he said reinforced the judges’ earlier views that the congressional districts were drawn with improper partisan goals.
‘‘We continue to lament that North Carolina voters now have been deprived of a constitutional congressional districting plan — and, therefore, constitutional representation in Congress — for six years and three election cycles,’’ Wynn wrote.
‘‘To the extent allowing the General Assembly another opportunity to draw a remedial plan would further delay electing representatives under a constitutional districting plan, that delay weighs heavily against giving the General Assembly another such opportunity.’’
He proposed several unusual ideas: appointing a special master to draw new districts, holding general elections without party primaries, or even turning the November elections into a primary and holding the general election sometime before the new Congress convenes in January.
Wynn and his fellow judges called for immediate briefing from the parties about which remedy to pursue.
The Supreme Court has never found that a state’s redistricting was so infected with politics that it was unconstitutional. This past term, it passed up the chance to do so with cases from Wisconsin and Maryland, disposing of them without deciding the merits.
The North Carolina case presented a stark example of partisan intent, with legislators making clear that the map was drawn to help one party over another.
‘‘I think electing Republicans is better than electing Democrats,’’ said David Lewis, a Republican member of the North Carolina General Assembly, addressing fellow legislators when they passed the plan in 2016. ‘‘So I drew this map to help foster what I think is better for the country.’’
He added: ‘‘I propose that we draw the maps to give a partisan advantage to 10 Republicans and three Democrats because I do not believe it’s possible to draw a map with 11 Republicans and two Democrats.’’
When voters went to the polls that fall, the 10-3 outcome was exactly as Lewis had predicted, even though Republican candidates won just 53 percent of the statewide vote.
Wynn said it should be clear that such partisan gerrymandering is unconstitutional.
‘‘A common thread runs through the restrictions on state election regulations imposed by Article I, the First Amendment, and the Equal Protection Clause: the Constitution does not allow elected officials to enact laws that distort the marketplace of political ideas so as to intentionally favor certain political beliefs, parties, or candidates and disfavor others,’’ he wrote.
Richard Hasen, an election law expert at the University of California at Irvine, said the case has national implications.
‘‘If the lower court orders new districts for 2018, and the Supreme Court deadlocks 4-4 on an emergency request to overturn that order, we could have new districts for 2018 only, and that could help Democrats retake control of the U.S. House,’’ he wrote on his blog.
The combined cases are Common Cause v. Rucho and League of Women Voters of North Carolina v. Rucho.